When you're making a mobile game, your app icon is one of the most important things to consider.

It's as crucial to the operation as a traditional game's box art. It's often the first thing a potential customer will see, and it must stand out on the crowded pages of the App Store.

But, it's not just about grabbing attention. Otherwise, every icon on iTunes would be a picture of Justin Bieber's face, or some boobs. No, there's an art to it, as well.

You've got to sum up everything about your game - its visual style, its themes, its characters, and its mood - in a picture that can be as small as a pinhead or as big as your desktop wallpaper.

So, today, we want to celebrate the single most important guys and gals in the industry. Here's to you, brave app icon designers. Here are the 20 greatest squares-with-slightly-rounded-off-corners we've seen all year.

Tap on any icon to be taken to the relevant review (or to the game's iTunes page, if we didn't find time to cover it this year).